1. Field of the Invention
This invention relates to levelling mechanisms for cabinets and, more particularly, to levelling mechanisms for uniformly supporting cabinets, such as refrigerator cabinets, on surfaces which slope from side to side.
2. Description of the Prior Art
Frequently, appliances, such as washing machines and refrigerators, are placed on sloping surfaces. Usually, manually adjustable supports are affixed to the front underside of the cabinets of the appliances. These supports are individually adjustable so that they can be employed for compensating for slope in a supporting surface from front to back and also for slope from side to side. The front supports, usually two in number, must often be adjusted to unequal lengths to compensate for the side-to-side slope in the supporting surface. Where the cabinet has two fixed rear supports, the weight of the cabinet may then cause the cabinet to rock on three of its four supports. This is particularly true of a refrigerator cabinet for it is very heavy when a normal amount of food is stored therein and, if not supported at all four of its corners, it will tend to rock or tilt. Of potentially greater concern, the weight of the refrigerator cabinet may cause twisting of the cabinet to bring all four supports into engagement with the supporting surface. The reason for this twisting is that the refrigerator cabinet is tall and not as rigid as more compact cabinets and tends to twist when loads are put on the cabinet by the food stored therein. This twisting action of the cabinet may cause distortion of the front face of the cabinet against which the door closes and thereby prevents the door gasket from properly sealing against the front face of the cabinet. If the sealing gasket of the refrigerator door does not seal well with the front face of the cabinet, then heat will leak into the refrigerator's food storage compartment and result in inefficient refrigeration and waste of electrical energy. Moreover, in the case of refrigerator-freezers which have two doors, one above the other or side by side, this twisting may prevent the doors from lining up well enough to be aesthetically acceptable.
Since the above-mentioned appliances are heavy and are often placed in confined areas, it is difficult or impossible to provide access to the rear supports for adjusting such supports to compensate for a sloping surface, particularly one which slopes from side to side. Hence, it is important to provide a means for effecting automatic adjustment of a rear support of the cabinet of the appliance to conform to the adjustment of the front supports in order that the cabinet may be uniformly supported, front and back, in an upright position, and to do this without requiring access to the rear supports.
The problem of providing self-adjusting supports for facilitating the levelling of appliances such as refrigerators and washing machines when such appliances are positioned on sloping floor surfaces is well-known, and the prior art discloses many examples of self-adjusting assemblies adapted especially for facilitating the levelling of such appliances without requiring access to the rear supporting structure and without requiring the use of manual procedures or tools. For example, U.S. Pat. No 3,954,241 teaches a self-adjusting assembly especially adapted for facilitating the levelling of an appliance, such as a washing machine or the like, on a sloping floor in order that the appliance be firmly positioned thereon. The assembly includes a pair of brackets located at the two rearmost, lower corners of an appliance, and a flexible cable element extending from one bracket to the other. Each bracket is provided with an independently adjustable leg member, with the members being interconnected by the cable. If both rear legs do not engage the floor, the leg which first engages the floor is forced upwardly by the weight of the cabinet. Through the cable, this causes a corresponding downward movement of the other leg until it is brought into engagement with the floor.
Another example of a support with automatic adjustment is taught by U.S. Pat. No. 3,880,388. The support is of the leg-type, comprising two vertically movable legs coupled together, in one embodiment, by a chain of rigid links encased by a tubular guide. The chain links are arranged such that as the weight of the supported structure causes one leg, which engages the surface upon which the structure is placed, to move upwardly, the other leg is urged downwardly until it engages the surface.
One problem with such prior art self-adjusting leg-type supports is that the mechanism employed is of complex and expensive construction.
In lieu of leg-type supports, some prior art cabinet structures employ a single, rear roller-type support in combination with two adjustable front supports. If a single roller-type support is utilized, it is necessary to provide a roller of reasonable length to assure adequate stability of the rear portion of a cabinet. This is especially important where the supporting surface is a soft floor covering. If the weight of the rear portion of the cabinet is supported on a short roller, this may result in a substantial depression in the supporting surface. Such depression would hinder the moving of the applicance from the confined space. However, where the two front supports are adjusted to unequal lengths on a floor which slopes from side to side and a roller of adequate length is employed, another problem is encountered in that one end of the rear roller may engage the floor covering and tend to press into the soft floor covering.
By this invention, those disadvantages and limitations of the prior art are overcome, and a support for appliances, such as refrigerators and washing machines, is provided which is simple in construction, can be manufactured economically and which readily and automatically adjusts itself appropriately for uniformly supporting the appliance on a surface which slopes from side to side.
Accordingly, it is an object of this invention to provide an improved construction of a rear levelling support for a cabinet whereby the support automatically adjusts itself to a supporting surface which slopes from side to side.
It is another object of this invention to provide such a rear levelling support which insures that the entire length of the support engages the supporting surface, thereby avoiding any concentration of the weight of the rear of the cabinet in a particular area of the supporting surface.
It is still a further object of this invention to provide a rear levelling support which minimizes depressions in a supporting surface and thereby facilitates the moving of an appliance such as a refrigerator cabinet from a confined space.